Cerebral endovascular embolization

What is endovascular embolization? 

Cerebral endovascular embolization is a procedure that uses a catheter to inject materials into certain blood vessels in the brain to block or close them off. The injected materials are called embolizing agents and can include coils, glue or very small particles. An endovascular embolization is performed by an interventional neuroradiologist either through the radial artery (wrist), distal radial artery (back of the hand) or femoral artery (groin) using X-rays for image guidance.

Reasons for a cerebral endovascular embolization

• To treat abnormalities of the blood vessels in the brain such as:
  
  • arteriovenous malformations (AVMs) – abnormal tangles
    
  • arteriovenous fistulas – irregular connections between arteries and veins
    
  • aneurysms – bulging or ballooning areas in parts of blood vessels walls
    
• To block off blood supply to a brain tumour 
  
• To close or protect an artery before surgery
  

Risks of cerebral endovascular embolization

The risk of cerebral endovascular embolization may increase depending on your child’s condition, age and health. Risks include:

• pain, bruising or bleeding in the groin, wrist or hand where the catheter was inserted
  
• infection where the catheter was inserted
  
• a bulge or weakness in the artery wall (pseudoaneurysm) where the catheter was inserted
  
• poor circulation to the leg, wrist or hand where the catheter was inserted
  
• clotting (blockage) of the accessed arteries 
  
• damage to the accessed arteries, such as dissection, rupture, or blockage
  
• bleeding in the brain or blockage of blood flow to part of the brain causing reduced function of organ and tissue (stroke, paralysis, organ loss)
  
• allergy to X-ray contrast dye
  

Planning for the procedure

You and your child may have a meeting with the interventional neuroradiology team before the procedure, if needed. During the visit, you should expect:

• A health assessment to make sure your child is healthy, and that it is safe to have general anaesthesia and to go ahead with the procedure.
  
• An overview of the procedure and a review of the consent form.
  
• Blood work, if needed.

Giving consent before the procedure

Before the procedure, the interventional neuroradiology team will go over how and why the procedure is done, as well as the potential benefits and risks. They will also discuss what will be done to reduce these risks and will help you weigh benefits against the risks. It is important that you understand all potential risks and benefits of the embolization and that all of your questions are answered. If your child is on any blood thinning medication, it is important to let the interventional neuroradiology team know. If you agree to the procedure, you can give consent for the embolization by signing the consent form. The procedure will not be done unless you give your consent.

How to prepare your child for the procedure

Before any treatment, it is important to talk to your child about what will happen. When talking to your child, use words they can understand. Let your child know that medicines will be given to make them feel comfortable during the procedure.

Children feel less anxious and scared when they know what to expect. Children also feel less worried when they see their parents are calm and supportive.

If your child becomes ill within two days before the procedure

It is important that your child is healthy on the day of their procedure. If your child starts to feel unwell or has a fever within two days before the embolization, let their health-care provider know. Your child’s procedure may need to be rebooked.

Food, drink and medicines before the procedure

• Your child’s stomach must be empty before general anaesthetic.
  
• If your child has special needs during fasting, talk to their health-care provider to make a plan.
  
• Your child can take their regular morning medicines with a sip of water up to two hours before the procedure.
  
• Medicines such as acetylsalicylic acid (ASA), clopidogrel, naproxen or ibuprofen, warfarin, or enoxaparin may increase the risk of bleeding. If your child is on any of these medications, consult with your child’s health-care provider and interventional neuroradiologist before the procedure to create a plan of care.

On the day of the cerebral endovascular embolization

Arrive at the hospital two hours before the planned time of your child’s procedure. You may be asked to arrive earlier or a few days prior to have some blood work done. Once you are checked in, your child will be dressed in a hospital gown, weighed and assessed. You will also be able to speak to the interventional neuroradiologist who will be doing the embolization and the anesthetist who will be giving your child medication to make them comfortable during the procedure.

During the embolization, you will be asked to wait in the surgical waiting area.

Your child will have medicine for pain

Children are given medicine for treatments that may be frightening, uncomfortable or painful. For embolization children are given general anaesthesia as well as local anaesthesia at the groin, wrist or hand where the catheter is inserted to make sure they are comfortable. 

How is a cerebral endovascular embolization done?

The interventional neuroradiologist will insert a flexible tube, called a catheter, into an artery in the groin (the femoral artery), or in the wrist (the radial or ulnar artery) or back of the hand (distal radial artery). The catheter is directed under X-ray guidance into the artery in the neck. A smaller catheter will be directed up to the area where the embolization is done. The embolizing agent will then be injected into the area of treatment. 

There are different types of embolizing agents such as liquid glue, metallic coils and embolic particles. Liquid glue acts as an adhesive and will quickly become hard and block the abnormal vessels. Metallic coils are made of platinum, and embolic particles are made of polyvinyl alcohol. Throughout this process, contrast dye is injected through the catheters. The dye is a clear, colourless liquid that helps to outline the arteries in the brain, so they show up on X-rays, which are used to take pictures of the arteries. 

Some children will be given blood thinners during the procedure to prevent the blood in the artery from clotting and blocking the artery.

When the procedure is finished, the catheter is taken out, and pressure is applied the artery in the groin, wrist or hand to stop any bleeding. If done through the groin, the insertion site will have a small clear dressing. If done through the wrist or back of the hand, your child will have a compression band on the hand or wrist specifically designed to stop bleeding at the access site.

After the cerebral endovascular embolization

In some cases, your child will be admitted to the intensive care unit (ICU) for observation immediately after the embolization is completed. In other cases, children are admitted to an inpatient unit. The interventional neuroradiologist will come and talk to you about the details of the procedure. Any follow-up imaging required—either a computed tomography (CT) or magnetic resonance imaging (MRI) scan—is usually done the following day. 

Going home

In most cases, children go home after two to three nights. For more details on how to care for your child after an endovascular embolization, please see Cerebral endovascular embolization: Caring for your child after the procedure.

Complications of the procedure

• Pain, swelling and bleeding at the access site
  
• Pain at the site of embolization 
  
• Fever, nausea and abdominal pain, usually within the first 72 hours (post-embolization syndrome)
  

Follow-up care

Your child will have a follow-up appointment in the neurointerventional or neurovascular clinic approximately two to six weeks after discharge.

When to seek medical attention

Call your child's health-care provider or go to the nearest Emergency Department right away if your child has any of the following:

• Sudden severe headache
  
• Sudden loss of vision in one or both eyes
  
• Sudden weakness on one side of the body, in a limb or on the face
  
• Sudden confusion or problems with speaking
  
• Active bleeding or swelling at the access site
  
• Pain, swelling or discoloration of the area below the access site
  

At SickKids

If you have any concerns in the first 48 hours, call the Image Guided Therapy (IGT) clinic at (416) 813- 7654 ext. 201804. Speak to the IGT clinic nurse during working hours or leave a non-urgent message.

If you have concerns and it is after working hours, see your primary care provider or go to the nearest Emergency Department. You can also call the Hospital for Sick Children switchboard at (416) 813-7500 and ask them to page a member of your child’s health-care team or the interventional radiology fellow on call.

For more information on fasting see Eating and drinking before surgery.

For more information on preparing your child for their procedure see Coming for surgery.